In vitro studies of the role of hexokinase in the metabolism of the intact lens of calf, rabbit and rat will be made. Rat lens will be incubated with ascorbic acid, hydrogen peroxide, and dehydroascorbic acid separately and chemical parameters will be measured: 86Rb uptake, glutathione level, ATP level, and Na-K ATPase level. Adding glucose to the incubation medium in addition to chemical reactants has a certain effect on the chemical parameters. The study of the biochemical changes occurring in a strain of mice with hereditary cataracts is being extended. Light and electron microscopic studies of these lenses are being continued.